"In one study, a Norwegian team identified a gene expression "signature" that distinguishes people with Alzheimer's from healthy individuals with an up-to-85 percent accuracy. "

"In other research, U.S. scientists reported that a combination of brain imaging techniques with sophisticated "pattern recognition software" could differentiate those with mild cognitive impairment (an early form of Alzheimer's) from those without the condition with 100 percent accuracy. "

"Finally, another U.S. study reveals that key diagnostic algorithms can predict an individual's six-year risk of developing dementia with at least 87 percent accuracy. "

"The results were announced Sunday at the Alzheimer's Association's International Conference on Prevention of Dementia in Washington, D.C."

"There currently is no cure for Alzheimer's disease, which the Alzheimer's Association now estimates affects nearly five million Americans. Existing treatments can slow progression of the brain-wasting disease, but by the time an individual has been diagnosed the disease has typically been at work for years and extensive, irreparable tissue damage has already occurred. Diagnosis is currently done simply by observing patients and is only about 80 percent accurate. "

"According to Greg Cole, associate director of research for the Geriatric Research Education and Clinical Center at the Greater Los Angeles Veterans Administration Medical Center, early detection of Alzheimer's disease can aid both patients and those scientists searching for a cure. "

"Patients benefit, he says, because earlier treatment can minimize tissue loss and thus improve quality of life. "

""It's like termite damage," he said. "You want to repair the damage before they destroy your house, you will be so much better off." "

"Pharmaceutical companies, on the other hand, can more confidently identify affected populations, which can reduce the size and cost of clinical trials, and thus enable them to perform more of them. "

"The Norwegian study, led by Anders Lonneborg, research director at DiaGenic ASA in Oslo, focused on gene expression profiling of an individual's blood."

"Using a 1,200-gene DNA microarray, his team could distinguish those with Alzheimer's disease from those who were healthy with 85 percent accuracy. Using a smaller set of genes (fewer than 96) and a technique called RT-PCR, the team achieved an accuracy of 79.5 percent. "

"But that was using samples from individuals whose disease was so far advanced that they could be diagnosed clinically, anyway. It remains to be seen, Cole said, if the test can pick out individuals much earlier in the disease process, when treatment might be more effective. "

"That, Lonneborg added, is the next step. "Now we will test [the diagnostic] on risk groups who have minor memory problems and see if we can predict who will develop Alzheimer's disease in a few years. This will be very interesting to see how it works," he said."

"A second study tackled early diagnosis using sophisticated brain imaging. The technique was developed by a team led by
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